This invention relates to clutches generally, and in particular to clutches that employ rollers to control the transmission of torque between the driving and the driven member.
There are many occasions where it would be useful to transmit torque to a driven member, such as a shaft, while allowing axial movement of the shaft relative to the driving member by applying rotating effort directly to the smooth surface of the shaft. For example, in drilling operations where the drill string that drives the bit is made up of a plurality of sections that are connected together by threads, torque is transmitted to the drill string to rotate the bit through a specially shaped upper section having a non-cylindrical outer surface. In other words, the driving member or Kelly is usually square or hexagonal in cross section and is located in a square or hexagonal opening in a drive bushing. The length of the non-cylindrical drive member limits the distance the drill can advance before another section has to be placed in the drill string at which time the drill string has to be moved out of the well bore or drill hole far enough to allow the driving member or Kelly to be unscrewed from the drill string and another section of drill pipe connected into the drill string.
It would be advantageous if the special drive section of a drill string could be eliminated thereby allowing sections of drill string to be continuously added to the drill string without raising the bit away from the bottom of the drill hole and without requiring the special drive section located at the top of the drill string, and it is an object of this invention to provide a clutch that will transmit torque to a member having a smooth cylindrical outer surface, such as drill pipe, while allowing axial movement of the drill string through the clutch.
It is another object of this invention to provide a clutch for driving a member having a smooth outer surface that can be quickly and easily engaged or disengaged to drive the member in one direction or in the opposite direction as desired.
It is a further object of this invention to provide a clutch for providing torque to a member having a smooth surface that can be quickly and easily disengaged to allow free rotation of the drill member relative to the driving member.
It is a further object of this invention to provide such a clutch that can be adapted to engage an external smooth, cylindrical surface for rotating such a member while allowing the free axial movement of either member relative to the clutch.
It is a further object of this invention to provide a circulating roller clutch that is adjustable to transmit torque to cylindrical bodies of various diameters.
These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification, including the attached drawings and appended claims.